Background event NameError: name 'app' is not defined

[gwsu2008]

Hi,

I got a NameError: name 'app' is not defined from this line
if (self.router.session.client_token not in app.event_namespace.token_to_sid):

I followed the sample code from https://reflex.dev/docs/events/background-events#terminating-background-tasks-on-page-close-or-navigation

The difference is that the class State is in a separate file. If I put the class State in the same file as the app.py where the app = rx.App() is defined, it works as expected.

Anyone seen this error and how to solve it?

Thanks

--Guang

[newelski]

[masenf]

@newelski why are you giving blatantly incorrect information?

If you even tried to run your own snippets you would see:

1. is a circular import and will fail right away
2. is a hullucination, given that self.router does not have an event_namespace attribute
3. doesn't make sense because the names in the package __init__.py are not automatically visible inside child modules, like myapp.state (this would still cause a circular import).

And aside, passing kwarg state to rx.App has been deprecated since 0.6 and removed since 0.7. Calling app.compile has been deprecated since 0.3.8. Neither of these constructs will work in the current version 0.8.4.

If you're going to post AI generated answers, you have a responsibility to make sure you're posting accurate information. Otherwise you're essentially spamming the discussion with unhelpful slop.

[masenf]

@gwsu2008 to give you an actual answer to your question.

There are two ways to get the app reference without circular import issues.

1. Perform the from myapp import app inside the body of the background event function itself. This will delay the import, allowing the module to be fully initialized before you try to get a reference to it.
2. Use from reflex.utils.prerequisites import get_app. Then get_app().app.event_namespace (note this will be None if the app is not running).